Datasheet

(Device Request) to the device. The device request is specified by the Setup data of length 8 bytes, and the direction is always
from the USB host to the USB device. Commonly used standard requests are shown in Table 7.
Table 7. Common Standard requests
Standard request Direction
SetAddress OUT
SetConfiguration OUT
GetDescriptor(Device/Configuration/String) IN
CDC class devices also support some class requests in addition to the standard requests. After the USB host obtains various
descriptor information of the CDC class device, it also sends some class requests to the USB device. Common Class requests
are shown in Table 8.
Table 8. Common Class requests
Class request Direction
SetLineCoding OUT
SetControlLineState OUT
GetLineCoding IN
The interrupt IN endpoint is not used in the CDC interface, so SetControlLineState class request cannot be
handled, ignore this class request.
NOTE
The GetLineCoding request is a request for the host to obtain the serial port attribute, including the baud rate, the stop bit, the
check type, and the number of data bits. The structure of the GetLineCoding request is shown in Table 9.
Table 9. GetLineCoding request structure
bmRequestType bRequestCode wValue wIndex wLength Data
10100001B GET_LINE_CODIN
G
Zero Interface Size of Structure Line Coding
Structure
The contents of Line Coding Structure are shown in Table 10.
Table 10. Line Coding Structure
Offset Field Size/byte Description
0 dwDTERate 4 Data terminal rate, in bits per
second
4 bCharFormat 1
Stop bits
0: 1 Stop bit
1: 1.5 Stop bit
2: 2 Stop
5 bParityType 1
Parity
0: None 3: Mark
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NXP Semiconductors
Software workflow chart
USB to Multi VCOM on K32L2 Series MCU, Rev. 0, November 2019
Application Note 14 / 25